span.tooltip {
    display: none;
    position: absolute;
    bottom: 100%;
    width: 100%;
    line-height: 20px;
    padding: 10px;
    font-size: 14px;
    text-align: center;
    color: #FFF;
    background: $black;
    box-shadow: 0px 4px 8px 0px rgba(0,0,0,0.3);
    z-index: 1;
    margin-bottom: -30px;
    margin-left: -10px;
}

span.tooltip:after {
    content: "";
    position: absolute;
    width: 0;
    height: 0;
    border-width: 10px;
    border-style: solid;
    border-color: $black transparent transparent transparent;
    bottom: -20px;
    left: 50%;
    margin-left: -10px;
}

a:hover > span.tooltip {
    display: block;
}